HEPA air purifiers - The misguided and mis-sold purifiers

Umar Shareef

High-efficiency particulate arrestance (HEPA) is a type of air filter known for its high filtration capability. A filter to qualify as HEPA needs to satisfy certain filtration standards. Market is flooded by different prefixes and suffixes to HEPA making real purchase of HEPA filter daunting task. In this article we bring you most updated HEPA guide in India so that you can make informed choice and do not waste your hard earned money on fake HEPA filters.
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HEPA filters is mesh of fibres randomly pruned to block the harmful particles. Generally the fibers are pruned as close as 0.3 micrometer making it effective in blocking harmful bacteria. HEPA filters have wide variety of applications including
Vacuum cleaners, airo planes and motor vehicles. Recently Tesla released a car Model X with HEPA filter.

Important properties of Air filters

Air purifiers pull the air inside and air filters block the harmful particles and push out clean and fresh air outside. There are few of properties of air filters based on which you can evaluate the quality of air filters and be certain about the purification.

The percentage of particles that filters can clean. Say the number is 95% meaning it actually removes 95% of particles in the air. It is good thing but at the same time it fail to remove 5% of particle. This information is usually mentioned in the product brochure.

The minimum diameter of the particle that filters can block. 0.3 micrometer diameter means it can clean the particle size of 0.3 or larger than 0.3 micrometer diameter size. This information is present in the product manual.

Minimum Efficiency Reporting Value (MERV) rating is a scale to measure efficiency of the filter, its ability to purify dust and other harmful particles. MERV scale is calibrated from 1 to 20. HEPA filter have good MERV rating. But some reason the manufacturers never mention this value in the the air purifier description.

HEPA filters Specifications

A randomly pruned map of fibres simple cannot qualify as HEPA filter. There are certain specifications a filter must meet to become HEPA. Unfortunately HEPA is simple acronym for High-efficiency particulate arrestance, the definition does not include the specification making it most misused term. Added to this fury two organizations, United States Department of Energy and European Union both released different criteria to qualify as HEPA.

HEPA filters specifications as per United States Department of Energy

The filter should remove 99.97% of airborne particles of 0.3 micrometers (µm) in diameter, then the filter is called as HEPA as per United states Department of energy(DOE).

These type of HEPA filters are very effective to combat Asthma and allergies. Asthma patients asthma attacks are significantly reduced after installing these HEPA filters in their households.

The specifications are very high and stringent. The HEPA filter air purifier as per DOE standard costs around minimum of Rs. 50,000, making it most expensive filters.

Marketers sometimes use term “True HEPA” to refer this. But the prefix ‘True’ is not authorized or approved by any organization so can be used or misused easily. So before buying HEPA look for percentage of particles in can purify and diameter of the particle. Do not go for simple terms like ‘True’.

The terms almost HEPA, HEPA-style, 99% HEPA, HEPA-type or HEPA-like means simple the filter is not HEPA.

HEPA filters specifications as per European Union

European union defined multiple classes of HEPA filters based on the percentage of air purification for given particles of size 0.3 micrometers (µm).

HEPA class

Total retention at 0.3 micrometer particle size

E10

> 85%

E11

> 95%

E12

> 99.5%

H13

> 99.95%

H14

> 99.995%

U15

> 99.9995%

U16

> 99.99995%

U17

> 99.999995%

You can see H14 class qualify as HEPA filter specification by Department of energy(DOE). But as we mentioned H14 class HEPA filters are very expensive. H13 class is next close to H14 or HEPA filter specifications by DOE.

Best Air purifiers with HEPA filters with Department of energy(DOE) specifications

As we have mentioned above they are super expensive and with in out research we have found that only BlueAir brand Air Purifiers qualified as HEPA filters.
We are presenting list of few HEPA air purifiers.

Best Air purifiers with H13 class HEPA filters

H13 HEPA air filters are next best alternatives to HEPA filters with Department of energy(DOE) specifications. Good thing is H13 class HEPA filters are economical. Here is the list of best H13 class HEPA filters

Missing information about HEPA filter in product description

Please see many product specifications have 99% of particles it can remove. But it is not accurate enough, precision is important. There is huge class difference between 99.0% and 99.7%.

Unfortunately many famous brands also have given the specifications like 99.* simple trying to mask their quality. Best example is Philips AC4012/10 36-Watt Tulip Air Purifier specifications missing vital information and specify about 2.5 micro metar filtration but percentage says 99.9% ***

The retailer's home page specifications are not accurate. Many cases the merchants entered wrong information. Best example same above philips air purifier. Please check HEPA filter details in brand product page.

Please post a comment if you find out additional information about HEPA air purifiers in the below post.

Short summary on selecting best HEPA air purifier

Check in the specification of air filter. The HEPA filter should remove 99.97% of airborne particles of 0.3 micrometers (µm) in diameter. It is costly and filter price starts from Rs. 50,000

The next best alternative is to go for H13 class HEPA filters. Price starts from Rs. 9,000.

Check the specifications at manufacturer's website as retails product page may have wrong information.